The epilepsy medication valproate is responsible for "severe malformations" in 2,150 to 4,100 children in France since the drug was first marketed in the country in 1967, according to a preliminary study by French health authorities.
Women who took the drug during pregnancy to treat epilepsy were four times more likely to give birth to babies with congenital malformations, said the report, jointly issued by the French National Agency for the Safety of Medicines (ANSM) and the national health insurance administration. 
"The study confirms the highly teratogenic" -- that is, capable of causing birth defects --- "nature of valproate," Mahmoud Zureik, scientific director of ANSM and co-author of the report, told AFP ahead of its release.